2. CATIA INTRODUCTION
CATIA (Computer Aided Three-dimensioning Interactive
Application) is a computer aided design tool programmed in
C++ language by Dassault Systems and marketed by IBM.
CATIA is the world’s leading CAD/CAM/CAE software.
It is also called as 3D ‘Product Lifecycle Management’ software
because it is also used at various industrial levels from design
process to manufacturing level of various products.
CATIA offers a solution to shape design, styling, surfacing
workflow and visualization to create modify, and validate
complex innovative shapes .
3. BAJA
Baja SAE is an intercollegiate design competition run by
the Society of Automotive Engineers (SAE).
The goal in Baja SAE racing is to design, build and race
off-road vehicles.
Baja is sponsored by “Mahindra & Mahindra Limited”.
4. CHASSIS
Roll Cage can be called as skeleton of a vehicle, its main
purpose is to form a frame or so called Chassis.
Types of Chassis
LADDER FRAME CHASSIS
TUBULAR SPACE FRAME CHASSIS
MONOCOQUE FRAME CHASSIS
ULSAB MONOCOQUE
BACKBONE FRAME CHASSIS
ALUMINIUM SPACE FRAME
CARBON-FIBBER MONOCOQUE
5. LADDER FRAME CHASSIS
Advantages-
The following are the advantages -
it is easy
cheap for hand build
Proves good for SUVs.
6. Disadvantages-
Torsional rigidity is very much lower especially when dealing
with vertical load or bumps.
Who use it ?
It is used by Most SUVs, classic cars, Lincoln Town Car, Ford,
Crown Victoria etc.
TUBULAR SPACE FRAME CHASSIS
7. 3 dimensional design
high-end sports cars adopt tubular space frame to enhance the
rigidity / weight ratio
tubes are welded together and forms a very complex structure
Advantages-
Very strong in any direction. (compare with ladder chassis and
monocoque chassis of the same weight)
Disadvantages-
Very complex.
Costly and time consuming to be built.
Impossible for robotised production.
Besides, it engages a lot of space,
Raise the door sill and result in difficult access to the cabin.
8. Who use it ?
It was used by all Ferrari before the 360M, Lamborghini Diablo,
Jaguar XJ220, Cater ham, TVR etc.
MONOCOQUE FRAME CHASSIS
Monocoque is a one-piece structure which defines the overall
shape of the car.
The floor pan, which is the largest piece, and other pieces are
press-made by big stamping machines.
9. Chassis is actually made by spot welding several pieces
together.
Advantages-
Cheap for mass production.
Inherently good crash protection.
Space efficient.
Disadvantages-
Heavy.
Impossible for small-volume production.
Who use it ?
Nearly all mass production cars, all current Porsche
10. ULSAB MONOCOQUE
Ultra Light Steel Auto Body (ULSAB)
It has the same structure as a conventional monocoque
It differs from its donor is in minor details - the use of "Hydro-form"
parts
Advantages-
Stronger and lighter than conventional monocoque without increasing
production cost.
11. Disadvantages-
Still not strong or light enough for the best sports cars.
Who use it ?
Opel Astra, BMW 3-series.
BACKBONE FRAME CHASSIS
12. It's strong enough for smaller sports cars but not up to the job
for high-end ones.
A strong tubular backbone (usually in rectangular section)
connects the front and rear axle and provides nearly all the
mechanical strength.
Advantages-
Strong enough for smaller sports cars.
Easy to be made by hand thus cheap for low-volume
production.
Simple structure benefit cost.
Disadvantages-
Not strong enough for high-end sports cars.
13. The backbone does not provide protection against side impact
or off-set crash.
Therefore it needed other compensation means in the body.
Cost ineffective for mass production.
Who use it ?
Lotus Esprit, Élan Mk II, TVR, Marcos.
ALUMINIUM SPACE FRAME
14. Consists of extruded aluminium sections, vacuum die cast
Components and aluminium sheets of different thicknesses.
It's quite complex and production cost is far higher than steel
monocoque.
Advantages-
Lighter than steel monocoque.
As space efficient as it.
Disadvantages-
Still expensive for mass production.
Who use it ?
Audi
15. CARBON-FIBBER MONOCOQUE
Most so-called "supercars" use carbon-fibber in body panels
only.
Kelvar is the most common Carbon-fibre used in motor
industry due to its highest rigidity-to-weight ratio.
Advantages-
The lightest and stiffest chassis.
16. Disadvantages-
By far the most expensive.
Who use it ?
McLaren F1, Bugatti EB110SS, Ferrari F50.
Chassis Design Considerations
Stiffness
Weight
Fitment and Packaging
Chassis Material Considerations
Steel
Aluminium
17. AISI 1018
The chassis can be broken up into three plane structures and two
tubular sections that connect them. Starting from the front of
the chassis and working back, these sections are-
Front Bulkhead
o It is “a planar structure that defines the forward plane of
the Major Structure of the Frame”.
18. Front Roll Hoop
o It is “a roll bar located above the driver’s legs, in proximity to
the steering wheel.”
19. Front Bulkhead Support System and Front Hoop Supports
Front hoop support
This is the structure which connects the front hoop and front
bulkhead.
20. Front bulkhead support system
The bulkhead support system was made by incorporating
the front suspension box in a support structure that
supports the front hoop support, bulkhead and
triangulated with the base rod
24. FINITE ELEMENT ANALYSIS
After finalizing the frame along with its material and cross
section, it is very essential to test the rigidity and strength
of the frame under severe conditions. The frame should
be able to withstand the impact, torsion, roll over
conditions and provide utmost safety to the driver without
undergoing much deformation. Following tests were
performed on the roll cage-
Front impact,
Side impact,
Rear impact,
Roll Over
25. Front impact analysis
Impact load calculation:
Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 10 for
extremely worst condition.
F = ma …. (1) = 325*10*10 = 32500 N
Impact Time= weight*(velocity/load)… (2)
= 325*(16.67/36000) = 0.15 seconds.
26. Rear impact analysis
Impact load calculation:
Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 10 for
extremely worst condition.
F = ma …. (1) = 325*10*10 = 32500 N
Impact Time= weight*(velocity/load)… (2)
= 325*(16.67/36000) = 0.15 seconds
27. Side impact Analysis
Impact load calculation:
Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 5 for
extremely worst condition.
F = ma …. (1) = 325*5*10
=16250N
28. Roll Over Analysis
Impact load calculation:
Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 2 for
extremely worst condition.
F = ma …. (1) = 325*2*10
=6500N